In recent years, the development of the manufacturing technology for a refrigerator or an air conditioner has been advanced due to a rapid development in the refrigeration technique and air-conditioning technique. Most effort is concentrated on providing a refrigerator or air conditioner with higher efficiency, less volume and lower weight, as well as an improved refrigerant. Meanwhile, the design and technical application for a heat-exchange tube used in the refrigerator or air conditioner has also been continuously improved. However, current heat-exchange tubes are all problematic in that a condensate film which functions as a thermal resistance develops when the refrigerant tries to condense, which thermal resistance adversely affects the heat transfer thus degrades the refrigeration efficiency. A most commonly used solution is to incorporate fins on the heat-exchange tube or directly form fins on the heat-exchange tube. However, heat resistance develops between the interface of the incorporated fins and the heat-exchange tube, which degrades the heat transfer efficiency of the heat-exchange tube. On other hand, fins directly formed on the heat-exchange tube are usually of small height, and it is difficult to achieve a relatively large heat transfer area on the heat-exchange tube. To increase the heat transfer area, one method is to stamp down a large portion of the fin so as to form a boss extending outwardly from the fin. However, heat transfer area for a heat-exchange tube so developed has not been increased markedly, since the only difference is that a portion of the original lateral surface is converted into a top surface perpendicular to the fin. Meanwhile, the boss is ineffective to attenuate or eliminate the condensate film, neither is it beneficial for a breaking off of the condensate film from the surface of the heat-exchange tube. Therefore, this boss configuration may not substantially improve or enhance the heat transfer property of the condensing heat-exchange tube and the condenser.